U.S. patent application number 16/563722 was filed with the patent office on 2020-03-26 for method and unit for forming an absorbent article.
The applicant listed for this patent is GDM S.p.A.. Invention is credited to Andrea DUCHINI, Aldo FUSARPOLI, Matteo PIANTONI, Mauro PIETRALUNGA, Marco ROSANI, Federico TOSCANI.
Application Number | 20200093648 16/563722 |
Document ID | / |
Family ID | 64557054 |
Filed Date | 2020-03-26 |
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United States Patent
Application |
20200093648 |
Kind Code |
A1 |
PIANTONI; Matteo ; et
al. |
March 26, 2020 |
METHOD AND UNIT FOR FORMING AN ABSORBENT ARTICLE
Abstract
A method for forming an absorbent article including a first
absorbent core and a second absorbent core which are superposed on
each other, includes feeding a first supporting web along a first
feed path in a first feed direction; placing a succession of first
absorbent cores on the first supporting web at a preset spacing;
feeding a second supporting web along a second feed path in a
second feed direction; placing a succession of second absorbent
cores on the second supporting web at the preset spacing; coupling
the first supporting web to the second supporting web such that
each first absorbent core is coupled to a corresponding second
absorbent core in a composite web including the succession of first
absorbent cores and the succession of the second absorbent cores
interposed between the first supporting web and the second
supporting web.
Inventors: |
PIANTONI; Matteo; (Albino
(Bergamo), IT) ; ROSANI; Marco; (Vailarate (Cremona),
IT) ; TOSCANI; Federico; (Castelleone (Cremona),
IT) ; DUCHINI; Andrea; (Castelleone (Cremona),
IT) ; PIETRALUNGA; Mauro; (Crema, IT) ;
FUSARPOLI; Aldo; (Offanengo (Bergamo), IT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
GDM S.p.A. |
Bologna |
|
IT |
|
|
Family ID: |
64557054 |
Appl. No.: |
16/563722 |
Filed: |
September 6, 2019 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61F 13/15764 20130101;
A61F 13/15699 20130101; A61F 13/15634 20130101 |
International
Class: |
A61F 13/15 20060101
A61F013/15 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 20, 2018 |
IT |
102018000008752 |
Claims
1. A method for forming an absorbent article of the type comprising
a first absorbent core and a second absorbent core which are
superposed on each other, the forming method comprising: a step of
feeding a first supporting web along a first feed path in a first
feed direction; a step of placing a succession of first absorbent
cores on the first supporting web at a preset spacing; a step of
feeding a second supporting web along a second feed path in a
second feed direction; a step of placing a succession of second
absorbent cores on the second supporting web at the preset spacing;
a step of coupling the second supporting web to the first
supporting web in such a way that each first absorbent core is
coupled to a corresponding second absorbent core in a composite web
comprising the succession of first absorbent cores and the
succession of the second absorbent cores interposed between the
first supporting web and the second supporting web.
2. The method according to claim 1, comprising a step of
compressing the first absorbent cores before the step of placing
the succession of first absorbent cores on the first supporting
web.
3. The method according to claim 1, comprising a step of
accelerating each first absorbent core before the step of placing
the succession of first absorbent cores on the first supporting
web, so as to space the first absorbent cores by the preset
spacing.
4. The method according to claim 2, wherein the step of compressing
the first absorbent cores is carried out before the step of
accelerating each first absorbent core.
5. The method according to claim 1, comprising a step of
compressing the second absorbent cores before the step of placing
the succession of second absorbent cores on the second supporting
web.
6. The method according to claim 1, comprising a step of
accelerating each second absorbent core before the step of placing
the succession of second absorbent cores on the second supporting
web, so as to space the second absorbent cores by the preset
spacing.
7. The method according to claim 5, wherein the step of compressing
the second absorbent cores is carried out before the step of
accelerating each second absorbent core.
8. The method according to claim 1, comprising a step of
compressing the composite web after the step of coupling the first
supporting web to the second supporting web.
9. The method according to claim 1, wherein the step of placing the
succession of second absorbent cores on the second supporting web
at the preset spacing is carried out while the second supporting
web moves along a curved line, specifically a circular arc.
10. The method according to claim 1, wherein the step of placing
the succession of second absorbent cores on the second supporting
web at the preset spacing is carried out just before the step of
coupling the first supporting web to the second supporting web.
11. The method according to claim 1, comprising a step of providing
an adhesive layer on the first supporting web before the step of
placing the first absorbent cores on the first supporting web.
12. The method according to claim 1, wherein the first absorbent
cores are smaller than the second absorbent cores.
13. The method according to claim 12, wherein each second absorbent
core of the second absorbent cores is placed on top of a
corresponding first absorbent core of the first absorbent cores
during the step of coupling the second supporting web to the first
supporting web.
14. The method according to claim 1, wherein the first supporting
web is the backsheet of an absorbent article, for example an
impermeable web, and the second supporting web is the topsheet of
the absorbent article.
15. The method according to claim 1, wherein the second feed path
is at least partly parallel to the first feed path and the second
feed direction is opposite to the first feed direction at least
where the first and second feed paths are parallel.
16. A unit for forming an absorbent article of the type comprising
a first absorbent core and a second absorbent core which are
superposed on each other, the forming unit comprising: a first feed
system for feeding a first supporting web along a first feed path
in a first feed direction; a first unit for forming and positioning
the first absorbent core disposed along the first feed path and
comprising a first placing station for placing the first absorbent
core on the first supporting web and comprising a first system for
positioning the first absorbent core on the first supporting web at
a preset spacing, the forming unit comprising: a second feed system
for feeding a second supporting web along a second feed path in a
second feed direction; a second unit for forming and positioning
the second absorbent core disposed along the second feed path and
comprising a second placing station for placing the second
absorbent core on the second supporting web and comprising a second
system for positioning the second absorbent core on the second
supporting web at the preset spacing, the forming unit comprising:
a coupling station for coupling the first supporting web to the
second supporting web, disposed downstream of the first placing
station and of the second placing station, the first and second
absorbent cores being superposed at least partly in the coupling
station in such a way that each first absorbent core is coupled to
a corresponding second absorbent core in a composite web comprising
the succession of first absorbent cores and the succession of
second absorbent cores interposed between the first supporting web
and the second supporting web.
17. The unit according to claim 16, wherein the first forming and
positioning unit comprises at least a first compression system for
compressing the first absorbent cores and disposed upstream of the
first placing station in a feed direction of the first absorbent
cores.
18. The unit according to claim 16, wherein the first positioning
system comprises a first accelerator for accelerating the first
absorbent cores to space two consecutive first absorbent cores of
the first absorbent cores by the preset spacing.
19. The unit according to claim 17, wherein the first accelerator
is disposed downstream of the first compression system in the feed
direction of the first absorbent cores.
20. The unit according to claim 16, wherein the second forming and
positioning unit comprises at least a second compression system for
compressing the second absorbent cores and disposed upstream of the
second placing station in a feed direction of the second absorbent
cores.
21. The unit according to claim 16, wherein the second positioning
system comprises a second accelerator for accelerating the second
absorbent cores to space two consecutive second absorbent cores of
the second absorbent cores by the preset spacing.
22. The unit according to claim 20, wherein the second accelerator
is disposed downstream of the second compression system in the feed
direction of the second absorbent cores.
23. The unit according to claim 16, wherein the second feed system
comprises a suction drum around which the second, preferably
permeable, supporting web is at least partly wound and the second
positioning system comprises at least one rotary carrier unit
movable along a curved line, specifically a circular arc,
substantially tangent to the suction drum in the placing station,
the second positioning system releasing the second absorbent cores
onto the second supporting web along the curved line.
Description
[0001] This application claims priority to Italian Patent
Application 102018000008752 filed Sep. 20, 2018, the entirety of
which is incorporated by reference herein.
BACKGROUND OF THE INVENTION
[0002] This invention relates to a unit and a method for forming an
absorbent article and, in particular, relates to a unit and a
method for forming the multilayer absorbent cores or the main
bodies of sanitary articles such as, for example, baby diapers,
sanitary napkins or the like.
[0003] In this description, for simplicity, express reference is
made to a diaper but without thereby limiting the scope of the
invention.
[0004] As is known, diapers comprise an absorbent pad or padding
which is normally enclosed between a permeable inner layer of
non-woven fabric and an impermeable outer layer of
polyethylene.
[0005] Market requirements have led diaper manufacturers to make
nappies having an absorbent pad consisting of a double absorbent
layer: a first, top layer or core, which is bigger and, in use,
directed towards the wearer, and underneath, a second, smaller
layer or core.
[0006] The relative position of the bigger absorbent core, on top
of the smaller one and offset forward to a variable extent, is
determined on the basis of the wearer's sex, age or special
needs.
[0007] Document US20130240125 describes a pad similar to the one
mentioned above and a method for making the pad.
[0008] According to what is described in that document, the smaller
absorbent core, provided with a wrapping, is first placed on a
polyethylene web, normally also called "backsheet", and the bigger
core is then placed on top of the smaller one and the composite web
thus formed is made to advance towards further processing
stations.
[0009] One disadvantage of making these products that way, apart
from the fact that the absorbent cores are placed in a wrapping,
lies in the difficulty of positioning the bigger core on the
smaller one and in keeping them in the right position as they
advance on the carrier layer.
[0010] Moreover, since the small core is generally much thicker
than the big core, it is very difficult to hold the big core
against the small one and against the layer underneath that and to
prevent loss of absorbent material from the cores, especially the
big ones.
SUMMARY OF THE INVENTION
[0011] In this context, the main technical purpose of this
invention is to propose a method and a unit for forming absorbent
articles such as will be unaffected by the disadvantages mentioned
above.
[0012] One aim of this disclosure is to propose a method and a unit
for forming an absorbent article such as will allow precisely
positioning the distinct absorbent cores making up the absorbent
pad.
[0013] Another aim of this disclosure is to propose a method and a
unit for forming absorbent articles such as will allow the
absorbent material to be effectively retained during the forming
process.
[0014] The technical purpose and aims specified are achieved by a
unit for forming absorbent articles according to claim 1 and by a
method for forming absorbent articles according to claim 28.
[0015] According to one aspect of it, this disclosure regards a
method for forming an absorbent article of the type comprising a
first, small absorbent core and a second, big absorbent core,
placed on top of each other.
[0016] According to one aspect of it, this disclosure regards a
method for forming an absorbent article comprising a step of
feeding a first supporting web along a first feed path in a first
feed direction and a step of placing a succession of first
absorbent cores on the first supporting web at a preset spacing
P.
[0017] The method comprises a step of feeding a second supporting
web along a second feed path in a second feed direction and a step
of placing a succession of second absorbent cores on the second
supporting web at the spacing P.
[0018] According to one aspect of it, the disclosure regards a
method for forming an absorbent article comprising a step of
coupling the first supporting web to the second supporting web in
such a way that each first absorbent core is coupled to a
corresponding second absorbent core in a composite web comprising
the succession of first absorbent cores and the succession of the
second absorbent cores interposed between the first supporting web
and the second supporting web.
[0019] Advantageously, the absorbent cores are first attached to or
positioned on a respective supporting web and then the distinct
webs provided with the respective absorbent cores are joined to
each other to form a composite web.
[0020] According to one aspect of it, the disclosure regards a
forming method comprising a step of compressing the first absorbent
cores before the step of placing the succession of first absorbent
cores on the first supporting web.
[0021] According to one aspect of it, the disclosure regards a
forming method comprising a step of accelerating each first
absorbent core before the step of placing the succession of first
absorbent cores on the first supporting web, so as to space the
first absorbent cores by the spacing P.
[0022] That way, thanks to an acceleration, which may be positive
or negative, it is possible to space the absorbent cores by the
required spacing as a function, for example, of the required size
or form of the absorbent article to be made.
[0023] Preferably, the step of compressing the first absorbent
cores is carried out before the step of accelerating each first
absorbent core.
[0024] According to one aspect of it, the disclosure regards a
forming method comprising a step of accelerating each second
absorbent core before the step of placing the succession of second
absorbent cores on the second supporting web, so as to space the
second absorbent cores by the spacing P.
[0025] That way, thanks to an acceleration, which may be positive
or negative, it is possible to space the second absorbent cores by
the required spacing as a function, for example, of the required
size or form of the absorbent article to be made.
[0026] Preferably, the step of compressing the second absorbent
cores is carried out before the step of accelerating each second
absorbent core.
[0027] According to one aspect of it, the disclosure regards a
forming method wherein the step of placing the succession of second
absorbent cores on the second supporting web at the spacing P is
carried out while the second web moves along a curved line,
specifically a circular arc.
[0028] That way, the absorbent core material not retained on the
web does not drop onto the web and thus does not dirty it.
[0029] Preferably, the step of placing the succession of second
absorbent cores on the second supporting web at the spacing P is
carried out just before the step of coupling the first supporting
web to the second supporting web.
[0030] According to one aspect of it, the disclosure regards a
forming method wherein the first absorbent cores are smaller than
the second absorbent cores, so that a big core is placed on a small
core once the respective supporting webs have been coupled to each
other.
[0031] According to one aspect of it, the disclosure regards a
forming method wherein the first supporting web is the backsheet of
an absorbent article and the second supporting web is the topsheet
of the absorbent article.
[0032] Advantageously, according to one aspect of it, the
disclosure regards a forming method wherein a small core is
positioned on or attached to the backsheet of the absorbent
article, a big core is coupled to the topsheet, and the backsheet
and topsheet, with respective layers of the absorbent core, are
joined to each other in such a way that each big core is positioned
on a respective small core.
[0033] According to one aspect of it, this disclosure regards a
unit for forming an absorbent article comprising a first system for
feeding a first supporting web along a first feed path in a first
feed direction; a first unit for forming and positioning the first
absorbent core, disposed along the first feed path and comprising a
first placing station for placing the first absorbent core on the
first supporting web and comprising a first system for positioning
the first core on the first supporting web at a spacing P, a second
system for feeding a second supporting web along a second feed path
in a second feed direction;
[0034] a second unit for forming and positioning the second
absorbent core, disposed along the second feed path and comprising
a second placing station for placing the second absorbent core on
the second supporting web and comprising a second system for
positioning the second absorbent core on the second supporting web
at the preset spacing P; a coupling station for coupling the first
supporting web to the second supporting web, disposed downstream of
the first placing station and of the second placing station.
[0035] According to one aspect of the disclosure, the first and
second absorbent cores overlap at least partly in the coupling
station in such a way that each first absorbent core is coupled to
a corresponding second absorbent core in a composite web comprising
the succession of first absorbent cores and the succession of the
second absorbent cores interposed between the first supporting web
and the second supporting web.
[0036] According to one aspect of the disclosure, the forming unit
comprises at least one compression system for compressing the
absorbent cores and disposed upstream of the first placing station
in a feed direction of the first absorbent cores.
[0037] According to one aspect of the disclosure, the first forming
and positioning unit comprises a first accelerator for accelerating
the first absorbent cores to space two consecutive first absorbent
cores of the first absorbent cores by the spacing P.
[0038] According to one aspect of the disclosure, the second
forming and positioning unit comprises at least a second
compression system for compressing the second absorbent cores and
disposed upstream of the second placing station in a feed direction
of the second absorbent cores.
[0039] Preferably, the second forming and positioning unit
comprises a second accelerator for accelerating the second
absorbent cores to space two consecutive second absorbent cores of
the second absorbent cores by the spacing P.
[0040] According to one aspect of the disclosure, the second feed
system comprises a suction drum around which the second supporting
web is at least partly wound and the second positioning system
comprises at least one rotary carrier unit movable along a curved
line, specifically a circular arc, substantially tangent to the
suction drum in the placing station, the second positioning system
releasing the second absorbent core onto the second supporting web
along the curved line.
BRIEF DESCRIPTION OF THE DRAWINGS
[0041] Further features and advantages of this solution are more
apparent in the non-limiting description of a unit and a method for
forming absorbent articles, as illustrated in the accompanying
drawings, in which:
[0042] FIG. 1 illustrates a unit for forming absorbent articles
according to this disclosure, in a schematic front view;
[0043] FIG. 2 illustrates a detail of a unit for forming absorbent
articles according to this disclosure, in a schematic front
view;
[0044] FIG. 3 illustrates an example of an absorbent article
obtainable with the forming method and unit according to this
disclosure, in a schematic plan view;
[0045] FIG. 4 is a transverse cross section through the plane IV-IV
of FIG. 3.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0046] With reference in particular to FIG. 1, the numeral 1
denotes a unit for forming absorbent articles according to this
disclosure.
[0047] FIGS. 3 and 4 illustrate an example of an absorbent article,
denoted by the reference numeral 100, obtainable with the forming
method and unit according to this disclosure.
[0048] The article 100 has a main direction of extension D, a front
portion and a rear portion.
[0049] In a preferred embodiment, the main extension is the
longitudinal one, that is the extension measured between the front
portion and the rear portion of the article 100.
[0050] The article 100 comprises an inner, liquid-permeable layer
101, that is, the layer which, in use, is directed towards a
generic wearer, and an outer layer 102.
[0051] The article 100 comprises an absorbent pad 103, sandwiched
between the inner layer 101 and the outer layer 102.
[0052] The pad 103, made with a forming unit and method according
to this disclosure, comprises a first absorbent core 104 and a
second absorbent core 105, which is bigger than the first absorbent
core 104, the two being coupled to each other.
[0053] The two absorbent cores 104, 105 are made, for example, from
an absorbent material consisting of a mixture of cellulose pulp,
also called "fluff", and superabsorbent material SAP.
[0054] In the embodiment illustrated by way of example, the
absorbent core 105 is bigger than the absorbent core 104 in the
main direction of extension D.
[0055] In the embodiment illustrated by way of example, the
absorbent core 105 is bigger than the absorbent core 104 in the
main direction of extension D.
[0056] The thickness S1 of the absorbent core 104, at right angles
to the positioning plane of the pad 103, is greater than the
thickness S2 of the absorbent core 105.
[0057] In a preferred embodiment, the thickness S1 is, for example,
twice as large as the thickness S2.
[0058] Generally speaking, according to common practice in the
trade, the first absorbent core 104 in a preferred embodiment is
hereinafter also called "small core" and the second absorbent core
105 is hereinafter also called "big core".
[0059] In a preferred embodiment, the layer 101 is what is known as
the "topsheet" of the article 100 and, in use, may be in direct
contact with the wearer.
[0060] Usually, the layer 101 is preferably a length of non-woven
fabric.
[0061] In the preferred embodiment, the outer layer 102 is
impermeable and is what is known as the "backsheet" of the
absorbent article 100--for example, a sheet of polyethylene.
[0062] The "topsheet" and the "backsheet" are joined to each other
in known manner to define the outer container of the article
100.
[0063] In alternative embodiments, the inner layer 101 and the
outer layer 102 are defined by lengths of non-woven fabric and form
what is known as an "envelope" for the pad 103.
[0064] The forming unit 1 comprises a feed system, schematically
represented as a block 2, for feeding a first supporting web
BS.
[0065] For example, the feed system 2 comprises rotary drums not
illustrated.
[0066] The web BS is intended to form the outer layer 102 of the
absorbent article 100 and is, for example, an impermeable web that
will form the backsheet of a diaper.
[0067] In an alternative use of the unit 1, the web BS is, for
example, a web of non-woven fabric that may become part of an
envelope for the absorbent pad 103.
[0068] In an alternative use of the unit 1, the web BS is, for
example, a web of non-woven fabric that may become the topsheet of
a diaper.
[0069] The web BS advances along a path P1, which is substantially
straight in the example illustrated but which may have other shapes
in alternative embodiments, in a direction V1.
[0070] The forming unit 1 comprises a unit 3 for forming and
positioning the absorbent core 104 and is preferably disposed along
the feed path P1 to form and place a succession of first absorbent
cores 104 on the web BS. As illustrated in particular in FIG. 2,
two consecutive cores 104 on the web BS are spaced by a spacing P
which, in practice, is the spacing in the succession of cores
104.
[0071] The forming and positioning unit 3 comprises a first and a
second mill 4, 5, of substantially known type, for preparing the
absorbent material used to make the absorbent cores 104.
[0072] The unit 3 comprises a forming drum 6 of substantially known
type, which, in the example illustrated, is rotatable clockwise
about an axis R6 and which is in communication with the mills 4, 5
to receive a flow of absorbent material on an outer peripheral
portion of it.
[0073] The absorbent material settles, for example, in suitable
suction housings in the form of a plurality of separate cavities,
each corresponding to a core 104, aligned with each other and
uniformly distributed along the peripheral portion of the drum 6
and capable of holding by suction the absorbent material being
carried.
[0074] The forming and positioning unit 3 comprises a compression
system 7 for compressing the absorbent cores 104 and disposed
downstream of the forming drum 6 in a feed direction V2 of the
cores 104.
[0075] In the embodiment illustrated by way of example, the
compression system 7 comprises a first transfer drum 8 for
transferring the cores 104, rotatable about an axis R8 and tangent
to the drum 6 from which, in use, it receives the cores 104.
[0076] A substantially known pressing device 9--for example, a
counter-roller--is coupled to the drum 8 in order to compress for a
first time the cores 104 advancing thereon.
[0077] The system 7 comprises a second transfer drum 10, rotatable
about an axis R10, located downstream of the drum 8 and tangent to
the latter, from which it receives the cores 104.
[0078] In the example illustrated, the compression system 7
comprises a second and a third pressing device 11, 12--for example,
counter-rollers--associated with the drum 10 to compress the cores
104 advancing thereon.
[0079] In alternative embodiments, the system 7, if present, may
comprise different combinations of transfer rollers and related
pressing devices, depending, for example, on the compacting
requirements of the cores 104.
[0080] Downstream of the compression system 7, the unit 3 comprises
an accelerator 13, rotatable about an axis R13 and of substantially
known type, which picks up the cores 104 from the drum 10 and
places them on the web BS at a spacing P in a placing station
14.
[0081] The accelerator 13 comprises, for example, a plurality of
carrier units 13a, rotating about the axis R13 and each configured
to advance a core 104.
[0082] The carrier units 13a are tangent to the web BS in the
placing station 14 and the directions V2 and V1 coincide; also, the
peripheral speed of the accelerator 13 corresponds substantially to
the feed speed of the web BS in the station 14.
[0083] Preferably, the unit 1 comprises a gluing unit,
schematically represented as a block G, upstream of the station 14
in the feed direction V1 of the web BS to spread a layer of glue or
adhesive at least to hold the cores 104 in place.
[0084] The unit 1 comprises a feed system 15 for feeding a second
supporting web TS.
[0085] For example, the feed system 15 comprises drums, one of
which is a suction drum, illustrated in FIG. 1, labelled 16,
rotatable clockwise about an axis R16.
[0086] The web TS is intended to form the inner layer 101 of the
absorbent article 100 and is, for example, a web of non-woven
fabric that will form the topsheet of a diaper.
[0087] In an alternative use of the unit 1, the web TS is, for
example, a web of non-woven fabric that may become part of an
envelope for the absorbent pad 103.
[0088] In an alternative use of the unit 1, the web TS is, for
example, an impermeable web that may become the backsheet of a
diaper.
[0089] The web TS advances in a direction V3 along a path P2 which
has a curved stretch at the drum 16.
[0090] The forming unit 1 comprises a unit 17 for forming and
positioning the absorbent core 105 and is preferably disposed along
the feed path P2 to form and place a succession of second absorbent
cores 105 on the web TS. As illustrated in particular in FIG. 2,
two consecutive cores 105 on the web TS are spaced by a spacing P
which, in practice, is the spacing in the succession of cores
105.
[0091] The forming and positioning unit 17 comprises a first and a
second mill 18, 19, of substantially known type, for preparing the
absorbent material used to make the absorbent cores 105.
[0092] The unit 17 comprises a forming drum 20 of substantially
known type, which, in the example illustrated, is rotatable
clockwise about an axis R20 and which is in communication with the
mills 18, 19 to receive a flow of absorbent material on an outer
peripheral portion of it.
[0093] The absorbent material settles, for example, in suitable
suction housings in the form of a plurality of separate cavities,
each corresponding to a core 105, aligned with each other and
uniformly distributed along the peripheral portion of the drum 20
and capable of holding by suction the absorbent material being
carried.
[0094] The forming and positioning unit 17 comprises a compression
system 21 for compressing the absorbent cores 105 and disposed
downstream of the forming drum 20 in a feed direction V4 of the
cores 105.
[0095] In the embodiment illustrated by way of example, the
compression system 21 comprises a transfer drum 22 for transferring
the cores 105, rotatable about an axis R22 and tangent to the drum
20 from which, in use, it receives the cores 105.
[0096] In the example illustrated, the compression system 21
comprises two pressing devices 23, 24--for example,
counter-rollers--associated with the drum 22 to compress the cores
105 advancing thereon.
[0097] In alternative embodiments, the system 21, if present, may
comprise different combinations of transfer rollers and related
pressing devices, depending, for example, on the compacting
requirements of the cores 105.
[0098] Downstream of the compression system 21, the unit 17
comprises an accelerator 25, rotatable about an axis R25 and of
substantially known type, which picks up the cores 105 from the
drum 22 and places them on the web TS at a spacing P in a placing
station 26.
[0099] The accelerator 25 comprises, for example, a plurality of
carrier units 25a, rotating about the axis R13 and each configured
to advance a core 105.
[0100] The carrier units 25a are tangent to the drum 16 in the
placing station 26 and the directions V4 and V3 coincide; also, the
peripheral speed of the accelerator 13 substantially corresponds to
the feed speed of the web TS, that is, the rotation speed of the
drum 16 in the station 26.
[0101] Advantageously, in the preferred case, where the web TS is
of non-woven fabric, hence permeable, the cores 105 are held on the
drum 16 by the suction provided by the latter.
[0102] The forming unit 1 comprises a coupling station 27 for
coupling the first supporting web BS to the second supporting web
TS and disposed downstream of the first placing station 14 and of
the second placing station 26.
[0103] Each first absorbent core 104 is coupled, in the station 27,
to a corresponding second absorbent core 105 in a composite web CT
comprising the succession of first absorbent cores 104 and the
succession of the second absorbent cores 105 interposed between the
first supporting web BS and the second supporting web TS.
[0104] In a preferred embodiment, the web BS defines the backsheet
102 of the absorbent article 100 and the web TS, the topsheet
101.
[0105] Preferably, the first absorbent core 104 is the small core
and the second absorbent core 105 is the big core.
[0106] That way, the unit 1 allows making an absorbent article 100
in which the small core 104 is associated with the backsheet and
the big core 105 is associated with the topsheet and each big core
105 is positioned on a small core 104 when the topsheet is coupled
to the backsheet.
[0107] In practice, each big core is positioned on a corresponding
small core by the respective supporting webs, thereby overcoming
the problems of prior art solutions because, according to this
disclosure, the big cores are not released directly onto the small
cores and on the web that supports the small cores.
[0108] The method for forming the absorbent article 100 according
to this disclosure comprises, in a preferred embodiment of it, a
step of feeding the first supporting web BS along the feed path P1
in the feed direction V1.
[0109] The web BS is, for example, an impermeable web of
polyethylene that will form the backsheet of a diaper.
[0110] The method comprises a step of placing a succession of first
absorbent cores 104 on the first supporting web BS at a spacing
P.
[0111] Preferably, the absorbent cores 104 will each constitute a
small core of a pad 103.
[0112] In the example embodiment where the web BS is, in
particular, impermeable, the forming method preferably comprises a
step of providing an adhesive layer on the first supporting web BS
before the step of placing the first absorbent cores 104 on it so
that the absorbent cores are held on the web BS as it advances.
[0113] Preferably, the absorbent cores 104 are formed in the
traditional manner, by feeding the absorbent material, comprising,
for example, cellulose pulp and superabsorbent material, to the
forming drum 6.
[0114] Before being placed on the web BS, the absorbent cores 104
are preferably subjected to compression to give the cores the
required density by expelling the air from the absorbent
material.
[0115] In the example illustrated, the absorbent cores 104 are
subjected to compression three times by the pressing devices 9, 11
and 12. In alternative embodiments, compression of the absorbent
cores 104 may be omitted or it may be performed in different
ways.
[0116] When the cores 104 are placed on the web BS, they are
suitably spaced at the spacing P in a substantially known manner,
for example by means of an accelerator which modifies the spacing
of the cores 104 after they have been formed.
[0117] Preferably, the cores 104 are spaced after being compressed,
making it possible, for example, to vary the size and form of the
article 100 made.
[0118] In practice, looking at FIG. 1, the web BS is fed in from
the left and the absorbent cores 104, after being suitably spaced,
are placed on it in the station 14.
[0119] The method for forming the absorbent article 100 according
to this disclosure comprises, in a preferred embodiment of it, a
step of feeding the second supporting web TS along the feed path P2
in the feed direction V3.
[0120] The web TS is, for example, a web of non-woven fabric
intended to form the topsheet of a diaper.
[0121] The method comprises a step of placing a succession of
second absorbent cores 105 on the second supporting web TS at a
spacing P, corresponding to the spacing P of the absorbent cores
104 on the web BS.
[0122] Preferably, the absorbent cores 105 will each constitute a
big core of a pad 103 since they are preferably larger than the
absorbent cores 104.
[0123] Preferably, the absorbent cores 105 are formed in the
traditional manner, by feeding the absorbent material, comprising,
for example, cellulose pulp and superabsorbent material, to the
forming drum 20.
[0124] Before being placed on the web TS, the absorbent cores 105
are preferably subjected to compression to give the cores the
required density by expelling the air from the absorbent
material.
[0125] In the example illustrated, the absorbent cores 105 are
subjected to compression twice by the pressing devices 23 and 24.
In alternative embodiments, compression of the absorbent cores 105
may be omitted or it may be performed in different ways.
[0126] When the cores 105 are placed on the web TS, they are
suitably spaced at the spacing P in a substantially known manner,
for example by means of the accelerator 25 which modifies the
spacing of the cores 105 after they have been formed.
[0127] Preferably, the cores 105 are spaced after being compressed,
making it possible, for example, in particular, to vary the size
and form of the article 100 made.
[0128] In practice, looking at FIG. 1, the web TS is fed in from
the right and the absorbent cores 105, after being suitably spaced,
are placed on it in the station 26.
[0129] Preferably, the step of placing the succession of second
absorbent cores 105 on the second supporting web TS at the spacing
P is carried out while the second web TS moves along a curved line,
specifically a circular arc which, in the example illustrated, is
defined by the drum 16.
[0130] That way, the absorbent material which makes up the cores
105 and which is not retained on the web TS does not drop onto the
web but is dispersed.
[0131] The method according to this disclosure further comprises a
step of coupling the first supporting web BS, provided with the
absorbent cores 104, to the second supporting web TS, provided with
the absorbent cores 105.
[0132] The step of coupling is carried out in such a way that each
first core 104 is coupled to a corresponding second core 105 in a
composite web CT comprising the succession of first absorbent cores
104 and the succession of the second absorbent cores 105 interposed
between the first supporting web BS and the second supporting web
TS.
[0133] Preferably, the step of placing the succession of second
absorbent cores 105 on the second supporting web at the spacing P
is carried out just before the step of coupling the first
supporting web BS to the second supporting web TS, in particular so
that as much of the absorbent material of the absorbent cores 105
as possible is able to be held within.
[0134] As mentioned, when the first absorbent cores 104 are the
small cores and the second absorbent cores 105 are the big cores,
the method according to this disclosure allows positioning the big
cores 105 on the small cores 104 in the composite web CT without
placing the big cores directly on the small cores, thereby
obviating the problems of the prior art.
[0135] The webs BS and TS are preferably joined by gluing.
[0136] In alternative embodiments, they are joined by other joining
methods, such as welding, for example.
[0137] Preferably, forming method according to this disclosure
comprises a step of compressing the composite web CT after the step
of coupling the first supporting web BS to the second supporting
web TS so as to join the two webs together more effectively and to
compact the absorbent pads 103.
[0138] In the example illustrated, the directions V1 and V3 are
preferably opposite and the webs TS and BS move towards each other
in parallel directions.
[0139] Preferably, also, the composite web CT moves away from the
station 26 along a line parallel to the incoming web TS but in the
opposite direction.
[0140] Advantageously, the absorbent cores 104, for example, the
small cores, and the absorbent cores 105, for example, the big
cores, are coupled to separate webs, for example, to the first web
BS and to the second web TS. This minimizes the positioning and
joining problems, as well as the problems connected with dispersal
of the absorbent material.
[0141] The supporting webs BS and TS are thus effectively
synchronized when they are joined to each other, so as to make
multilayer pads 103 that are well "wrapped" in the composite web
CT.
[0142] As mentioned, in a preferred embodiment, the composite web
CT is made up of the topsheet, the backsheet and the multilayer
pads of the nappies and undergoes further processing for forming
and packaging the nappies.
[0143] The multilayer pads are preferably of the type comprising a
small core and a big core which, in use, is directed towards the
wearer.
[0144] In an embodiment, and depending on the materials used, the
absorbent article made in the unit 1 is an absorbent pad which
comprises a big core and a small core and which is sandwiched
between two webs of non-woven fabric.
[0145] In an embodiment, the big cores, which are joined to the
respective supporting web, are positioned on the small cores, which
have been previously joined to the respective supporting web.
[0146] In an embodiment, the small cores, which are joined to the
respective supporting web, are positioned on the big cores, which
have been previously joined to the respective supporting web.
[0147] Joining the absorbent cores first to the supporting webs and
then to each other makes it possible to obviate the problems of
positioning one set of cores on top of the other set and holding
them in place.
* * * * *